SSL devices generally use semiconductor light emitting diodes (LEDs), organic light-emitting diodes (“OLEDs”), and/or polymer light emitting diodes (“PLEDs”) as sources of illumination rather than electrical filaments, a plasma, or a gas. FIG. 1 is a cross-sectional diagram of a portion of a conventional indium-gallium nitride (“InGaN”) LED 10. As shown in FIG. 1, the LED 10 includes a substrate 12 (e.g., silicon carbide, sapphire, gallium nitride, or silicon), an N-type gallium nitride (GaN) material 14, an InGaN/GaN multi quantum well (MQW) 16, and a P-type GaN material 18 on one another in series. The LED 10 also includes a first contact 20 on the P-type GaN material 18 and a second contact 22 on the N-type GaN material 14.
The GaN/InGaN materials 14, 16, and 18 have a wurtzite crystal formation in which hexagonal rings of gallium (or indium) are stacked on top of hexagonal rings of nitrogen atoms. According to conventional techniques, the GaN/InGaN materials 14, 16 and 18 are typically grown along a direction generally perpendicular to the hexagonal rings of gallium (or indium) and nitrogen atoms. As discussed in more detail later, the growth direction of the GaN/InGaN materials 14, 16 and 18 may negatively impact the optical efficiency of the LED 10. Accordingly, several improvements in the optical efficiency of LEDs may be desirable.